Studies on long lasting optical properties of Eu2+ and Dy3+ doped di-barium magnesium silicate phosphors

Di-barium magnesium silicate phosphors doped with europium and dysprosium were prepared under a weak reducing atmosphere. X-ray diffraction pattern of the sample was also done that confirmed the proper preparation of the phosphor. Scanning electron microscope (SEM) images confirmed that the sample has regular surface and uniform grain size distribution. Comparative studies of phosphorescence decay of Ba2MgSi2O7:Eu2+, Dy3+ phosphors with different concentration of Dy3+ were done. The phosphor with 0.5/1.5 mol% of Eu/Dy, exhibited optimum green color afterglow properties. This emission is expected to arise due to transition of Eu2+ ions from any of the sublevels of 4f65d1 configuration to 8S7/2 level of the 4f7 configuration. For a suitable trap depth, the trap concentration is expected to be proportional to the concentration of Dy3+. These traps are responsible for holding the charge career for a reasonable time, subsequently for increasing the time of afterglow. Hence, optimum Dy3+ concentration produces the longer afterglow duration with higher intensity of luminescence signals. Trap depth were also calculated using thermoluminescence glow curve which was indicative of formation of traps suitable for long afterglow.

A series of Ba2MgSi2O7:Eu2+, Dy3+ were synthesized using high temperature solid state reaction technique for different concentration of Dy3+ keeping concentration of Eu2+ constant. Afterglow curves for these phosphors were recorded, that indicated, best afterglow was observed when concentration ratio of Eu:Dy was 1:3.Figure optionsDownload as PowerPoint slide